Such a flow adjustment valve is, for example, known from DE 196 19 125 C2. Here, the throttle arrangement is formed by a measuring jack, which is arranged ahead of the throttle unit. The pressure measuring channels branching off on each side of this measuring jack are led out laterally, so that the pressure measuring connections are located in lateral faces of the valve housing and have an angle in relation to the pipe stub of approximately 45° and an angle in relation to each other of 90°.
Such a flow adjustment valve serves the purpose of hydraulically balancing a hydraulic system, for example a pump operated hot water heating. The balancing is meant to cause that the flow amounts in different sections of the fluid-filled systems correspond to certain specifications.
For this purpose, the pressure on both sides of the throttle arrangement is measured. If the size of the throttle arrangement is known, the flow can be calculated on the basis of the pressure. The flow can be changed by means of the throttle unit. It is also known to use the throttle unit as throttle arrangement. In this case, a scale or another display device is needed, from which the actual opening degree of the throttle unit can be seen.
Independently of that, it is necessary to have the opportunity of measuring the pressure on both sides of the throttle arrangement and thus the pressure difference over the throttle arrangement.
Such a flow adjustment valve is only seldomly activated, usually at the start up of such a hydraulic system or after changes of the hydraulic system. In order to ensure that it does not otherwise interfere, it is often mounted in an inaccessible spot, for example under floors or in ducts. This, however, makes the setting of the flow difficult for an installer, as the flow adjustment valve is difficult to access. Particularly, it is often difficult to insert measuring probes in the pressure measuring connections. This will in many cases require the installer to have a substantial amount of skill.